Optimizing $\alpha''$-Fe$_{16}$N$_2$ as permanent magnet via alloying

TL;DR

This study uses first-principles calculations to explore how 27 different alloying elements affect the magnetic properties of Fe$_{16}$N$_2$, aiming to enhance its potential as a permanent magnet material.

Contribution

It systematically analyzes the effects of multiple alloying elements on Fe$_{16}$N$_2$'s magnetic properties, identifying promising candidates like Co, Mo, and W for experimental validation.

Findings

20 elements can substitute into Fe$_{16}$N$_2$ without strong site preference.

All alloying elements reduce saturation magnetization.

Alloying significantly modifies magnetic anisotropy.

Abstract

Based on systematic first-principles calculations, we investigate the effects of 27 alloying elements on the intrinsic magnetic properties of Fe$_{16}$N$_2$, in order to further optimize its properties for permanent magnet applications. Analysis on the thermodynamic stabilities based on formation energy and distance to the convex hull reveals that 20 elements can be substituted into Fe$_{16}$N$_2$, where there is no strong site-preference upon doping. It is observed that all alloying elements can essentially reduce the saturation magnetization, whereas the magnetic anisotropy can be significantly modified. In terms of the Boltzmann-average intrinsic properties, we identify 8 elements as interesting candidates, with Co, Mo, and W as the most promising cases for further experimental validations.